In many cases an electrical device comprises a circuit board furnished with electrical components. The electrical device can be, for example but not necessarily, an Internet Protocol “IP” router, an Ethernet switch, a MultiProtocol Label Switching “MPLS” switch, and/or an Asynchronous Transfer Mode “ATM” switch. The circuit board comprises a body made of one or more layers of electrically insulating material and electrical conductors on one or both of the surfaces of the circuit board and/or between the layers of the electrically insulating material. Each of the electrical components can be, for example, an integrated circuit such as a processor or a memory, or a discrete component such as a resistor, a capacitor, an inductor, a transistor, or a diode. Furthermore, the electrical device may comprise also other elements than electrical components. Examples of the other elements are elements related to cooling arrangements and optical elements.
The optical elements may comprise, for example, one or more indicator light sources that are controlled according to the operational status of the electrical device. The operational status indicated by the one or more indicator light sources can be for example: “running”, “stand-by”, “energized”, “activated”, “armed”, “de-activated”, “fault”, etc. In many cases, the indicator light sources are not in the place where the indicator lights are displayed to a user of the electrical device. For example, the indicator light sources are not necessarily in a control panel of the electrical device but the electrical device comprises one more light guides made of light conducting material and configured to conduct the indicator lights to the control panel where the indicator lights are displayed to the user. In conjunction with some applications, the light guides are called light pipes.
There has been, and there still is, a trend to decrease the physical dimensions of electrical devices as well as to increase the number of connectors and/or other equipment or instruments located on control panels of the electrical devices. Therefore, the room available for light guides of the kind mentioned above has decreased and is still decreasing. Hence, there is a need for technical solutions that are suitable for reducing the room needed for light guides.